The Harvard/Boston City ACTU has four clinical centers for trials for promising drugs or drug combinations in the treatment of HIV- infection or its complications. The four centers are the Massachusetts General Hospital (MGH), Beth Israel Hospital (BIH), New England Deaconess Hospital (NEDH) and Boston City Hospital (BCH). This collaborative group draws from a wide patient catchment area in Massachusetts and throughout New England, including all socio-economic groups. Both sexes are represented and there is a wide diversity of racial and ethnic groups included in these studies. All adult risk groups participate, and the numbers of under-represented and minority populations participants has risen steadily over recent years. Studies are conducted of antiretrovirals, as well as of agents active against opportunistic pathogens, cancers, and metabolic or neurologic complications of HIV infection. Both Phase I and Phase II-III studies are performed. The current proposal is to extend these studies and to broaden the net of underrepresented populations included in clinical trials. The Harvard/Boston City ACTU has made major contributions to existing knowledge concerning the pathogenesis and therapy of HIV infection, and has contributed significantly to the Scientific Agenda and leadership of the existing ACTG. Harvard has participated in the ACTG quality control program since its inception and is conducting critical studies on viral resistance and quantitation, as well as on immunopathogenesis. It plans to expand these research efforts within the framework of the ACTG Advanced Technology Laboratory Program.